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Tuesday, April 2, 2019

Ice-cliff failure via retrogressive slumping

Geology, (2019) ;

Ice-cliff failure via retrogressive slumping


Retrogressive slumping could accelerate sea-level rise if ice-sheet retreat generates ice cliffs much taller than observed today. The tallest ice cliffs, which extend roughly 100 m above sea level, calve only after ice-flow processes thin the ice to near flotation. Above some ice-cliff height limit, the stress state in ice will satisfy the material-failure criterion, resulting in faster brittle failure. New terrestrial radar data from Helheim Glacier, Greenland, suggest that taller sub-aerial cliffs are prone to failure by slumping, unloading submarine ice to allow buoyancy-driven full-thickness calving. FullStokes diagnostic modeling shows that the threshold cliff height for slumping is likely slightly above 100 m in many cases and roughly twice that (145–285 m) in mechanically competent ice under well-drained or low-melt conditions.

1 comment:

Anonymous said...

Thank you for sharing